<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
    <title>简单的html5 File测试 for pic2base64</title>
    <style>
    </style>
    <script>
        window.onload = function(){
            var input = document.getElementById("demo_input");
            var result= document.getElementById("result");
            var img_area = document.getElementById("img_area");
            if ( typeof(FileReader) === 'undefined' ){
                result.innerHTML = "抱歉，你的浏览器不支持 FileReader，请使用现代浏览器操作！";
                input.setAttribute( 'disabled','disabled' );
            } else {
                input.addEventListener( 'change',readFile,false );}
        }
        function readFile(){
            var file = this.files[0];
//这里我们判断下类型如果不是图片就返回 去掉就可以上传任意文件
            if(!/image\/\w+/.test(file.type)){
                alert("请确保文件为图像类型");
                return false;
            }
            var reader = new FileReader();
            reader.readAsDataURL(file);
            reader.onload = function(e){
                //result.innerHTML = '<img src="'+this.result+'" alt=""/>';
                result.innerHTML = this.result;
                img_area.innerHTML = '<div class="sitetip">图片img标签展示：</div><img src="'+this.result+'" alt=""/>';
            }
        }
    </script>
</head>
<body>
<input type="file" value="sdgsdg" id="demo_input" />
<textarea id="result" rows=30 cols=300></textarea>
<p id="img_area"></p>
</body>
</html>